Make XML project ready to support NetBeans platform.
Tools module contains Java generators (DTD2SAX, DTD2DOM) and also
programing language neutral generators (XML2DTD, DTD2HTML, DTD2CSS).
When there will be e.g. Forte for C++, then Java generators does not make sense
to have them there.
Therefore, separate Java generators from xml-tools module and make xml-java
module for it.